The Backbone Pro Xbox Edition looks like an improvement over the pre-existing One controller in nearly every way. It's still a USB-C shell that wraps around a phone or related device, but the actual controller is now more in league with an actual Xbox gamepad. It features full-size control sticks, hall effect triggers and two customizable back buttons. Most of the inputs can be remapped.
If you've ever thought "it'd sure be nice to have just one controller to use between my phone, tablet, and TV," then the Backbone Pro might be made for you. Backbone's newest gamepad has the same phone-hugging design as its 2020 predecessor, but comes with a handful of distinct features - the most notable being that it can be paired via Bluetooth to any number of devices, not just phones.